Cellular Respiration and Energy Production

Vocabulary terms and definitions covering the stages, enzymes, and transport mechanisms of cellular respiration.

Hemoglobin

The protein inside red blood cells that binds to and carries oxygen throughout the bloodstream to tissues.

Iron

An essential element required for hemoglobin synthesis; low levels cause decreased red blood cells, lower oxygen transport, and reduced $ATP$ production.

Rough Endoplasmic Reticulum

The organelle containing attached ribosomes that synthesizes membrane proteins, including glucose transport proteins.

Golgi Apparatus

The organelle that modifies membrane transport proteins after synthesis in the rough endoplasmic reticulum before they are inserted into the cell membrane.

Glycolysis

Stage one of cellular respiration occurring in the cytoplasm, where glucose is split and oxidized, yielding a net total of $2\text{ ATP}$ and $2\text{ NADH}$.

Hexokinase

An enzyme synthesized on free ribosomes in the cytoplasm that catalyzes the transfer of a phosphate group from hydrolyzed $ATP$ onto glucose to make glucose-6-phosphate.

Phosphoglucoisomerase

The glycolytic enzyme that isomerizes glucose-6-phosphate into fructose-6-phosphate.

Free Ribosomes

Ribosomes floating unattached in the cytoplasm that synthesize proteins and enzymes functioning within the cytoplasm, such as glycolytic enzymes.

Vitamin B

A group of essential dietary nutrients (including niacin and riboflavin) consumed in foods that the body requires to produce the electron carrier NAD.

Pyruvate Dehydrogenase

An enzyme that oxidizes pyruvate by removing hydrogens to reduce NAD to NADH, while releasing a carbon atom as $CO_2$.

Oxidative Decarboxylation

A type of biochemical reaction in which a molecule is oxidized through the loss of hydrogens/electrons while simultaneously releasing a carboxyl group as $CO_2$.

Citric Acid Cycle

Stage two of cellular respiration located in the mitochondrial matrix that begins with citrate, completely dismantling remaining carbons into $CO_2$ while yielding NADH, $FADH_2$, and $ATP$.

Citrate

The six-carbon molecule formed at the entry of the citric acid cycle by combining acetyl-CoA with a four-carbon compound.

Electron Transport Chain

Stage three of cellular respiration located on the inner mitochondrial membrane where electrons from NADH and $FADH_2$ are transferred through membrane proteins to establish a proton gradient.

ATP Synthase

The enzyme at the end of the electron transport chain that utilizes the flow of protons through its rotor mechanism to generate $ATP$.